Method and apparatus for increasing fluid flow

ABSTRACT

A method and fluid flow device for increasing the rate of flow of a fluid by inducing angular velocities in the flow entering the device thereby to reduce the upstream static pressure, and carrying the angular velocities through the device where it is nullified before leaving the device, thereby to increase the downstream static pressure. Reducing the static pressure of the fluid entering the device and increasing the static pressure of the fluid leaving the device results in two forces of acceleration tending to increase the rate of flow through the device. In one embodiment, the device is a venturi-type nozzle having a forward set of baffles in the converging section and a rear set of baffles in the diverging section, and in another embodiment, the device is a teardrop-shaped flow restriction in a conduit and has a forward set of corrugated baffles and a rear set of corrugated baffles.

States Patent Keyser [54] METHOD AND APPARATUS F OD IINCREAMNG FLUIDFLUW [72] Inventor: Edwin J. Keyser, 14513 Mulholland Drive, LosAngeles, Calif. 90024 22 Filed: Aug. 14,1970

211 Appl.No.: 63,691

ZZL

3,027,143 3/1962 Furgerson et a1 138/39 Primary Examiner-Houston S.Bell, Jr.

Attorney-Fulwider, Patton, Rieber, Lee & Utecht 5 ABSTRACT A method andfluid flow device for increasing the rate of flow of a fluid by inducingangular velocities in the flow entering the device thereby to reduce theupstream static pressure, and carrying the angular velocities throughthe device where it is nullified before leaving the device, thereby toincrease the downstream static pressure. Reducing the static pressure ofthe fluid entering the device and increasing the static pressure of thefluid leaving the device results in two forces of acceleration tendingto increase the rate of flow through the device. In one embodiment, thedevice is a venturi-type nozzle having a forward set of baffles in theconverging section and a rear set of baffles in the diverging section,and in another embodiment, the device is a teardrop-shaped flowrestriction in a conduit and has a forward set of corrugated baffles anda rear set I of corrugated baffles.

16 Claims, 8 Drawing Figures PATENTED JANZSISYE 3,636,983

sum 2 BF 2 METHOD AND APPARATUS I OR INCREASING FLUID FLOW BACKGROUND OFTHE INVENTION This invention relates to fluid flow devices and methodsof controlling fluid flows, and has particular reference to a method anddevice for increasing a fluid flow.

It is well known that when a fluid moves through a horizontal, constantdiameter conduit in a condition of parallel, laminar, steady state flow,the velocity, dynamic pressure and static pressure flow parameters donot vary from location to location along the conduit. If aconverging-diverging restriction, such as a venturi or a centralteardrop-shapped body, is placed in the constant diameter conduit andthe velocity, dynamic pressure and static pressure parameters of floware measured at locations sufficiently spaced upstream and downstream oneither side of the restriction, the values will remain unchanged, againassuming parallel, laminar, steadystate flow through the conduit.

An analysis of the fluid flow through the restriction shows that thefluid accelerates as it enters the converging section of the restrictionand then decelerates after passing through the throat to the divergingsection. As the fluid initially enters the restriction, the direction ofthe fluid velocity is purely longitudinal and is parallel with thecenter line of the conduit. Upon reaching the converging section,however, the fluid is forced to constrict radially and, in so doing,accelerates both longitudinally and transversely.

In a venturi-type restriction, for example, the flow is constrictedradially inwardly in the converging section. As a result, the flowparticles develop transverse velocity components thereby creatingdynamic pressure components, both of which are directed inwardly towardsthe center line of the conduit. Similarly, if the restriction is ateardrop-shaped body centrally positioned in the conduit, the flow willbe constricted radially outwardly in the converging section, and boththe transverse velocity components and dynamic pressure components ofthe flow particles will be outwardly directed.

Thus, as the flow is constricted by the converging section, transversevelocity and dynamic pressure components appear which are directedradially of the conduit. The transverse velocity and dynamic pressurecomponents appear with the first constriction of the flow and arepresent throughout the length of the converging section. Upon reachingthe throat, however, the fluid flow is again purely longitudinal and thetransverse velocity and dynamic pressure components disappear.

In a similar, but reversed manner, after the flow passes through thethroat, it expands in the diverging section and decelerates, and againdevelops transverse velocity and dynamic pressure components which, inthe case of the venturi restriction, are now directed outwardly, and inthe case of the teardrop-shaped restriction, are now directed inwardly.This deceleration of the fluid continues until the flow returns toparallel laminar flow longitudinally of the conduit.

Since a dynamic pressure rise is necessarily accompanied by acorresponding reduction in static pressure, the appearance of atransverse velocity component is accompanied by a correspondingreduction in static pressure. Thus, the appearance of transversevelocity components in the converging and in the diverging sectionsnecessarily results in the lowering of static pressures.

However, the appearance of the transverse velocity components of theflow particles in the converging and diverging sections has little, ifany, effect on the net static pressure in the restriction since thetransverse velocities appear and disappear with the transverse dynamicpressures independently within each section of the restriction. That is,the transverse velocity appearing in the converging section alsodisappears in the converging section so that any static pressurereduction resulting from the transverse velocity appearance is offset bya corresponding rise in static pressure accompanying the disappearanceof the transverse velocity as the flow enters the throat. Therefore,there is virtually no change in the rate of flow through the restrictioneven though changes in static pressure do take place.

SUMMARY OF THE INVENTION The present invention resides in a method anddevice for increasing the rate of flow of a fluid stream through arestriction of the foregoing general character by inducing transversevelocity components in the fluid stream in the converging section,thereby converting static pressure into dynamic pressure, reacting thetransverse velocity components with the device to change the directionof the components, transferring the dynamic pressure through the fluidstream, and subsequently converting the dynamic pressure back to staticpressure in the diverging section. The conversion of static pressure todynamic pressure in the converging section lowers the static pressure inthe converging section and acts to accelerate fluid into therestriction, while the conversion of dynamic pressure back to staticpressure in the diverging section increases the static pressure in thediverging section and tends to accelerate the fluid downstream out ofthe restriction, the combined effect of the two accelerations being toincrease the flow rate through the restriction.

The flow particles having transverse velocity components are reactedwith the device to change the directions of the components from linearvelocities to angular velocities. The transverse angular velocities areproduced in the converging section by a first set of baffles which reactagainst the flow particles having transverse linear velocities. Thetransverse angular velocities then are carried by the longitudinal flowthrough the converging section to the diverging section where a secondset of baffles reacts against the transverse angular velocities tonullify the angular velocities and thus raise the static pressure.

In one embodiment, the device is in the form of a venturi nozzle withthe first and second sets of baffles each comprising a plurality of flatplates positioned with their flat surfaces parallel with the center lineof the nozzle and offset from the radial so that the flat surfaces areperpendicular to the transverse velocity components and parallel withthe longitudinal velocity components in both the converging anddiverging sections. In a second embodiment, the device is in the form ofa teardrop-shaped flow restriction and employs radial, corrugatedbaffles as both the first and second sets of baffles.

The second embodiment finds particular application in turbulent flowsituations and produces angular velocity com ponents 12 the flow in theform of random turbulence by reacting the first set of baffles againstthe transverse linear velocity components of the flow. The second set ofbaffles in the diverging section reacts against the flow to nullify therandom turbulence induced in the converging section and thereby raisethe static pressure in the diverging section.

The features and advantages of the present invention will be apparentfrom the following detailed description taken in conjunction with theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a longitudinal sectional view of afluid conduit within which a nozzle embodying the novel features of thepresent invention is placed, and illustrating a means for carrying outthe method of this invention;

FIG. 2 is a side elevational view, partly in cross section, of theconduit and nozzle of FIG. I, the cross section being takensubstantially along line 22 of FIG. I;

FIG. 3 is a sectional view of the conduit and nozzle of FIG. I, takensubstantially along the line 3-3 of FIG. I;

FIG. 41 is a fragmentary perspective view of the conduit and nozzle ofFIG. I;

FIG. 5 is a view similar to FIG. I showing the alternative embodimentwith a teardrop-shaped restriction in the flow conduit;

FIG. 6 is a cross-sectional view taken substantially along line 66 ofFIG. 5;

FIG. 7 is a cross-sectional view taken substantially along line 77 ofFIG. and

FIG. 8 is a fragmentary perspective view of the conduit and restrictionof FIG. 5.

DETAILED DESCRIPTION As shown in the drawings, the present invention isembodied in a fluid flow device or body, designated generally by thereference numeral 10, and a method and improvements in the device forreducing the static pressure in an upstream portion of the device andincreasing the static pressure in a downstream portion in such a manneras to produce an increase in the rate of flow of a fluid through thedevice. In this instance, referring to the embodiment of FIGS. 1 through4, the device 10 is in the form of a venturi-type nozzle having acircular cross section throughout its length and having a frontconverging section 24 and a rear diverging section 26. The nozzle 10 iscoaxially mounted in a portion of a cylindrical conduit in which a fluidmoves from left to right, as indicated by the arrows 22.

Preferably, the converging section 24 has a forward concave inside wallportion 28 extending rearwardly (to the right in FIG. I) from the frontend 30 and terminating at a forward convex inside wall portion 32. Theforward convex portion 32 extends rearwardly from the forward concaveportion 28 and merges with the concave portion with a smooth andcontinuous curve between the front end 30 and the throat 34 of thenozzle 10. The diverging section 26, in cross section, is a mirror imageof the converging section 24 and has a rear convex inside wall portion36 and a rear concave inside wall portion 38, the diverging sectionpreferably being of substantially the same size and shape as theconverging section so that the nozzle 10 is symmetrical on each side ofthe throat 34.

In accordance with the present invention, the flow of fluid through thenozzle 10 is increased by inducing transverse velocity components in theflow and reacting these components with the nozzle to produce angularvelocities in the converging section 24, thereby converting staticpressure into dynamic pressure, transmitting the dynamic pressure in theform of angular velocities through the fluid stream, and subsequentlyconverting the dynamic pressure back to static pressure in the divergingsection 26, thereby increasing the static pressure in the divergingsection. The reduction in static pressure in the converging section 24tends to accelerate fluid into the nozzle 10 while the increased staticpressure in the diverging section 26 tends to accelerate fluiddownstream out of the nozzle. The combined effect of these twoaccelerating forces is a tendency to increase the rate of flow throughthe nozzle I0.

Toward these ends, a first set of baffles 42 is positioned in theconverging section 24 of the nozzle 10 to react against a portion of theflow, imparting angular velocities to the flow and converting staticpressure to dynamic pressure. The angular velocities are carried by theflow to the diverging section 26 where a second set of baffles 44 reactagainst the flow to nullify the angular velocities and thus convert thedynamic pressure back to static pressure.

Referring particularly to FIGS. 1 and 2, the first set of baffles 42herein comprises four thin flat plates having radially outer edges 48curved to fit the arc of the forward concave portion 28 of theconverging section 24. These plates 42 are secured, for example bywelding, to the forward concave portion 28 and are regularly spaced sothat each projects into the flow passage through the nozzle 10.

The four forward plates 42 are arranged with their flat surfaces 50lying in planes parallel with the longitudinal direction of fluid flowthrough the nozzle 10, each plate being perpendicular to the adjacentplate on each side and being offset from and parallel to a radius sothat the inner edges 51 of all plates are tangent to a common cylinder(not shown) having a longitudinal axis which coincides with thelongitudinal axis of the nozzle. The second set of baffles 44 similarlycomprises four thin flat plates arranged, as best seen in FIG. 3, in amanner substantially like that of the first set 42, discussed above.

Assuming the fluid flow entering the converging section 24 is initiallyin a condition of parallel laminar, steady-state flow, the fluid beginsto be constricted by the concave portion 28. As shown by the dashed lineflow path 52, in the absence of the first set of baffles 42, the forwardconcave portion 28 forces the flow to accelerate radially inwardlytowards the centerline of the nozzle 10, and hence the flow has aresultant velocity (V,) which includes not only the longitudinalvelocity component (V,,), but also a transverse velocity component (V,)directed inwardly towards the center line of the conduit.

The flow then continues to accelerate radially inwardly until it reachesthe forward convex portion 32 where the transverse velocity component(V,) begins to decelerate as the flow moves towards the nozzle throat34. At the throat 34, the flow again is purely longitudinal with notransverse velocity components.

It is noteworthy that, as the flow accelerates through the forwardconcave portion 28, the appearance of transverse velocity components inthe flow necessarily results in reductions of the static pressure in theregions of the velocity increases, since all increased in dynamicpressure must be accompanied by corresponding static pressurereductions. In the forward convex portion 32, however, the transversevelocity is dissipated, and thus produces a corresponding increase instatic pressure in this portion of the converging section 24. Since thestatic pressure rise in the convex portion 32 is due to the dissipationof the transverse velocities introduced in the concave portion 28, thestatic pressure rise is substantially equal to the static pressurereduction in the concave portion. Thus, the net static pressure changein the converging section 24 of the nozzle 10 is virtually zero.

A similar action takes place in the diverging section 26 of the nozzle10 in the absence of the second set of baffles 44. As the flow leavesthe throat 34, it expands through the rear convex portion 36 and thestatic pressure is reduced by the appearance of transverse velocitycomponents in the flow which are directed radially outwardly away fromthe center line of the nozzle 10. In the rear concave portion 38,however, the static pressure again rises as the transverse velocitiesare dissipated, thus making the net static pressure change virtuallyzero over the length of the diverging section 26.

With the present invention, the first set of baffles 42 in the forwardconcave portion 28 enables the fluid, as it passes through theconverging section 24, to transfer static pressure to the divergingsection 26. By virtue of the position and configuration of the first setof baffles 42, as the fluid is constricted in the forward concaveportion 28, some of the fluid particles having transverse velocitycomponents strike the flat surfaces 50 of the forward plates 42 and aredeflected. Thus, the first set of baffles 42 reacts against the flow andimparts uniform turbulence to the flow in the form of angularvelocities. The angular velocities imparted to the flow by the first setof baffles 42 cause the flow to twist or rotate in a clockwise directionin FIGS. 2 and 4, as it moves through the converging section 24.

Since the first set of baffles 42 only reacts against the transversevelocity components of the flow and converts these components intoangular velocities, the longitudinal velocity components aresubstantially unaffected by the first set of baffles which have theirflat surfaces 50 parallel with the centerline of the conduit. Further,there is no counterpart to the first set of baffles 42 to restrict theflow rotation in the forward convex portion 32, and therefore the flowcontinues to rotate completely through the converging section 24 andthrough the throat 34 of the nozzle 10.

As mentioned before, the appearance of transverse velocity components inthe forward concave portion 28 necessarily is accompanied bycorresponding reductions in static pressure in this portion. Thereaction of the forward plates 42 against the flow, in effect, transfersthe energy of the transverse velocity components into the energy oftransverse angular velocities,

and therefore, this energy is carried completely through the convergingsection 24 without being dissipated in the forward convex portion 32.

Thus, the static pressure reduction accompanying the transverse velocitycomponent appearance in the forward concave portion 24 is not offset orcompensated for by a corresponding static pressure rise in the forwardconvex portion 32 as there is nothing in the forward convex portion tonullify the transverse angular velocities in the flow imparted by thefirst set of baffles 42. The net effect, then, is a reduction in theoverall static pressure in the converging section 24 over any reductionthat would have taken place in the absence of the first set of baffles42, as discussed above.

In fact, the rotation imparted to the flow by the reaction of the firstset of baffles 42 increases as the flow moves through the convergingsection 24 of the nozzle since the radius continually decreases. Thus,since the rate of rotation is inversely proportional to the length ofthe radius, the rate of rotation of the flow is a maximum at the throat34.

As the flow leaves the throat 34 and enters the rear convex portion 36,the radius of the nozzle 32 increases and the angular velocities of theflow begin to decelerate. In the rear concave portion 34, the second setof baffles 44 reacts against the angular flow and imparts transverseangular impulses opposite in direction to that of the flow. Thus, thesecond set of baffles 44 acts against the flow to dispel or nullify thetransverse angular velocities of the flow imparted by the first set ofbaffles and carried over to the diverging section 26 from the convergingsection 24.

As a result of nullifying the transverse fluid velocities carried overfrom the converging section 24 in the form of angular velocities, thereis a corresponding rise in the static pressure in the rear concaveportion 38 of the nozzle It) which is over and above any static pressurerise which would have resulted in the absence of the first and thesecond sets of baffles 42 and 44. Thus, the first set of baffles 42functions to redirect the transverse velocity components of flow in sucha manner that these components of velocity are, in effect, transmittedthrough the fluid stream to the downstream diverging section 26 beforebeing nullified by the second set of baffles 44. This, then, produces anet reduction in the static pressure in the converging section 24 and anet increase in the static pressure in the diverging section 26, each ofwhich is substantially in excess of that which would have been observed,in the absence of the first and second sets of baffles 42 and 44.

To ensure that all flow rotation has been nullified before flow leavesthe nozzle 10, an additional set of cross baffles 54 is provided at therear end 56 of the nozzle. In this instance, the cross baffles 54 aretwo generally rectangular plates having flat sides 57 which extenddiametrically across the rear end 56 of the nozzle lit and divide theflow passage into four equal pie-shaped segments. The flat sides 57 ofthe crossed baffles 54 are parallel with the longitudinal direction offlow and the plates preferably are made relatively thin so that nosubstantial obstruction to the longitudinal flow is presented. Shouldany appreciable angular momenta escape being nullified by the second setof baffles 44, the crossed baffles 54 will react against the flow anddissipate the residual flow rotation.

By lowering the static pressure in the converging section 24, anincrease in the velocity of the flow through the nozzle llt) results.The reduced static pressure created by the transverse angular velocitiesimparted to the flow by the first set of baffles 42, acts as a force toaccelerate fluid into the nozzle it) to balance the static pressurereduction. As the velocity of flow into the nozzle it) increases, themagnitude of the transverse velocity components in the convergingsection 24 correspondingly increases, thus increasing the transverseangular velocities and further reducing static pressure.

Theoretically, in the absence of any retarding forces such as friction,fluid viscosity and the like, the flow into the nozzle 10 would continueto accelerate until no static pressure existed in the converging section24. This, of course, does not happen in an actual situation and the flowaccelerates only until the inherent flow retarding forces which producestatic pressures are in balance with the forces of acceleration of theflow through the nozzle 22.

Similarly, the increased static pressure in the diverging section 26,resulting from nullification of "the angular velocities carried overfrom the converging section 24, acts as a force of acceleration tendingto force the fluid out of the nozzle it). Theoretically, the rise instatic pressure in the diverging section 26 should equal the staticpressure reduction in the converging section 24. Again, however, due tothe inherent retarding forces acting on the fluid in the nozzle 10, theactual static pressure rise is somewhat less than the correspondingstatic pressure reduction in the converging section 24.

The fluid flow device ill) of the embodiment of FIGS. 5 through 4 takesthe form of a teardrop-shaped central restriction or body in the flowpassage of the cylindrical conduit 26', and provides a means fortransferring; static pressure in a manner generally similar to that ofthe embodiment of FIGS. ll through 4, parts of this embodiment whichcorrespond to those of the embodiment of FIGS. 1 through 4 beingdesignated by corresponding primed reference numerals. In this instance,the central restriction it) has a hemispherical forward wall 58 and aconical rear wall 60, the forward portion of the conical rear wall beingcurved to merge with the rear portion of the hemispherical forward wallto provide a smooth and continuous arcuate interconnection between theforward and rear walls.

The converging section 24 in this embodiment is defined by the flowpassage between the forward wall 53 and the cylindrical conduit 20', andthe diverging section 26 is defined by the flow passage between the rearwall 60 and the conduit, with the throat 34' defined as the point ofmaximum flow passage restriction, herein being the line ofinterconnection between the forward wall and rear wall sections. Thefirst set of baffles 42 in the embodiment of FIGS. 5 through 8 comprisesa series of forward plates which herein are corrugated and which projectoutwardly from the forward wall 58 and lie along radial plates includingthe centerline of the conduit 20.

The corrugations of the forward plates 42' preferably are arranged topresent a series of flat surfaces 62 which extend longitudinallyparallel with the longitudinal direction of flow and perpendicular tothe radial direction of the conduit 20'. The second set of baffles 44'is arranged in a manner generally similar to that of the first set ofbaffles 42', and comprises a series of rear plates which are preferablycorrugated, and which are aligned axially with the forward plates 42 andextend radi ally from the rear wall 60.

As shown by the dashed flow path 64 illustrated in FIG. 5, fluid flowingin the conduit 20' in a condition of parallel, laminar steady stateflow, is constricted by the forward wall 58 of the central restriction10 so as to converge towards the wall of the conduit. As a result ofbeing constricted, the fluid particles pick up velocity components whichare transverse to the longitudinal direction of flow, the direction ofthe transverse components being radially outwardly towards the wall ofthe conduit 20.

In the absence of the first and second sets of baffles 42' and 44',respectively, the net effect produced by the appearance of transversevelocity components in the converging section 24' of the embodiment ofFIGS. 5 through 8 would be substantially like that discussed inconjunction with the embodiment of FIGS. 1 through 4 in the absence ofthe first and second sets of baffles 42 and 44. The net change in staticpressure over the length of the converging section 24' would besubstantially zero since the transverse components initially accelerateand then decelerate to zero as they move over the forward wall 58 andreach the throat 34'. Similarly, in the absence of the second set ofbaffles 44' in the diverging section 26', there would be no appreciablerise in static pressure following the dissipation of transversevelocities appearing in the diverging section as the flow is returned toparallel, laminar steady state flow after the flow leaves the centralrestriction area.

However, the first and second sets of baffles 42 and 44', respectively,provide means for lowering the static pressure in the converging section24 and transferring the static pressure to the diverging section 26. Theembodiment of FIGS. through 8 finds primary application in situationswhere random turbulent flow can be expected, and employs a randomturbulent flow mechanism for effecting the static pressure transfer.

It is generally recognized that as a fluid flows over a surface, thefluid is subjected to a stationary resisting force at the surface, thisforce being due primarily to friction and acting in a direction oppositeto the direction of fluid flow. The friction force is proportional tothe fluid flow velocity and increases in magnitude as the flow velocityincreases. Due to fluid viscosity, the friction force at the surfaceacts not only on the fluid particles immediately adjacent the surface,but also produces an angular stress on fluid particles travelling withthe flow and spaced some distance from the surface. As long as the flowis laminar, there is an equal and opposing angular strain in the fluidstructure to resist the angular stress resulting from the friction forceat the surface.

For every fluid flow, there is an approximate point beyond which thefluid structure cannot resist the angular stress placed upon it by thefriction force at the surface. As a result, when the velocity of thefluid flow reaches a point where the fluid structure can no longerresist the angular stress, the flow collapses suddenly and laminar flowbecomes random turbulent flow and the individual fluid particles acquiresubstantial angular momenta and no longer follow predictable paths, butrather travel in unpredictable small circular currents and vortices.

With the appearance of random turbulent flow, a substantial decrease instatic pressure in the region of this turbulence takes place. This isattributable to a conversion of static pressure to dynamic pressure asthe flow collapses and numerous small vortices appear, some of thevortices rotating in a direction opposite to that of the net rotationalflow direction. This pressure conversion is produced by the stationaryangular stress at the surface which redirects the average molecularmotions within the fluid particles without changing the total energycontent of the fluid. Although the average linear velocity of the fluidparticles within the flow is reduced slightly from its original value asthe random turbulence condition is produced, the total velocityincreases substantially due to the additional angular motions of thefluid particles. Similarly, due to the substantial total velocityincrease, the static pressure in the random turbulence region is reducedto only a fraction of its original value.

The first set of baffles 42 in the embodiment of the fluid flow device10' of FIGS. 5 through 8, reacts against a portion of the flow toproduce transverse angular velocities in the flow in the form of randomturbulence in the converging section 24'. The conversion of staticpressure to dynamic pressure reduces the static pressure in theconverging section 24', this dynamic pressure then being transmitted tothe diverging section 26. This is accomplished by redirecting a portionof the fluid particles which have transverse velocities into a conditionof random turbulence in such a manner that the longitudinal velocitycomponents are substantially unaffected.

As the fluid is initially restricted by the forward wall 58 of therestriction 10', the fluid particles pickup transverse components ofvelocity, as previously discussed. A portion of the fluid particleshaving transverse velocity components encounter the flat surfaces 62 ofthe corrugated first set of baffles 42' and angular stresses areproduced on the fluid which are directed radially inwardly and areproportional in magnitude to the transverse velocity magnitudes. Byaccelerating the fluid in such a manner that the transverse velocitycomponents have a magnitude within the range whereby the fluid can nolonger resist the stationary angular stresses, the flow is caused tocollapse and convert from laminar to random turbulent flow.

As mentioned before, this conversion results in a substantial reductionin the static pressure in the converging section 24', there being acorresponding increase in the dynamic pressure represented by transverseangular velocities of the fluid, approximately equal to the staticpressure reduction. Since the fluid turbulence induced by the corrugatedfirst set of baffles 42 results only from a reaction with the transversevelocity components of the flow, the numerous small vortices formedrotate generally around axes which are parallel to the longitudinal flowdirection.

It is noteworthy that the baffles 42' of the first set form an outwardlydiverging transverse flow passage in the otherwise converging section 24between the front of the forward wall 58 and the throat 34'. It is wellknown that diverging fluid passage tends to induce random turbulencewhile a converging fluid passage tends to reduce such turbulence. Thus,the random turbulence induced by the transverse reaction of the firstset of baffles 42' tends to increase as the fluid approaches the throat34 since the area between the baffles increases.

The induced random turbulence does not substantially effect thelongitudinal flow velocity and is not nullified in the convergingsection 24'. Thus, the dynamic pressure represented by the vortices ofthe transformed, and redirected transverse velocity components iscarried completely through the converging section 24' with a resultantlowering of the static pressure in the converging section beyond anystatic pressure reduction which would have taken place in the absence ofthe first set of baffles 42', as previously discussed.

As the fluid enters the diverging section 26', the second set of baffles44 reacts against the fluid turbulence as the flow decelerates tonullify the random turbulence and return the flow to a condition ofparallel laminar flow. As in the case with the first set of baffles 42,the second set of baffles 44' reacts only against the turbulent fluidparticles moving in a direction transverse to the longitudinal directionand thus does not substantially effect the longitudinal flow velocity.

As the random turbulence fluid enters the diverging section 26, the flowvortices encounter the flat surfaces 62 of the corrugated second set ofbaffles 44 and stationary angular stresses are set up which are directedradially outwardly, and hence in opposition to the direction of rotationof the flow vortices. It should be noted that the second set of baffles44' form an inwardly converging flow passage from the throat 34' to therear end of the rear wall 60, this transverse convergence having theeffect of reducing random turbulence. Therefore, due to the flowdeceleration, the stationary angular stresses and the converging baffles44', the random turbulence carried over from the converging section 24'is nullified in the diverging section 26'.

The nullifying of this carried'over fluid turbulence results in acorresponding lowering of the dynamic pressure and increasing of thestatic pressure in the diverging section 26. Thus, the static pressurereduction in the converging section 24' represented by the inducedrandom turbulent flow, is carried over to the diverging section 26'where the fluid turbulence is nullified producing a correspondingincrease in static pressure.

As in the case with the embodiment of FIGS. 1 through 4, the resultobtained by lowering the static pressure in the converging section 24and increasing the static pressure in the diverging section 26, is toincrease the rate of flow through the conduit 20'. Thus, although theembodiment of FIGS. 5 through 8 employs a random turbulent flowmechanism for effecting the transfer of static pressure, the resultobtained is generally similar to the result obtained with the embodimentof FIGS. 1 through 4 which employs a uniform turbulence flow mechanism.

From the above, it should be evident that the method of the presentinvention enables the rate of flow of a fluid stream through a fluidflow device to be increased over that heretofore possible. Further, thefluid flow device 10 of the present invention provides a means wherebythe static pressure on the leading surface can be reduced andtransferred to the trailing surface in accordance with the novel methodof the invention.

it will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention.

I claim: l. The method of reducing static pressure on a leading surfaceof a body in a fluid stream comprising the steps of:

inducing transverse velocity components in the fluid stream along theforward surface thereby converting static pressure of the fluid todynamic pressure and correspondingly thereby reducing the staticpressure on the forward surface;

reacting the transverse velocity components with the body along theforward surface to change the direction of the components fortransmission of the dynamic pressure through the fluid stream;

and transmitting the dynamic pressure through the fluid stream away fromthe forward surface.

2. The method as defined in claim l in which the transverse velocitycomponents in the fluid stream are reacted with the body to impartturbulent flow to the stream, the dynamic pressure being transmittedaway from the forward surface as tur' bulent flow.

3. The method as defined in claim 2 in which the turbulent flow isimparted by reacting the transverse velocity components with the body toproduce angular velocities in the flow.

t. The method of reducing static pressure on a forward surface of a bodyin a fluid stream while increasing static pressure on a rear surface ofthe body, said method comprising the steps of:

inducing transverse velocity components in the fluid stream along theforward surface thereby converting static pressure of the fluid todynamic pressure and correspondingly thereby reducing the staticpressure on the forward sur face;

reacting the transverse velocity components with the body along theforward surface to change the direction of the components fortransmission of the dynamic pressure through the fluid stream;

transmitting the dynamic pressure through the fluid stream to the rearsurface;

and reacting the dynamic pressure with the body along the rear surfaceto reconvert the dynamic pressure to static pressure on the rearsurface.

5. The method as defined in claim 4 in which the transverse velocitycomponents in the fluid stream are reacted with the body to impartturbulent flow to the stream, the dynamic pressure being transmittedthrough the stream to the rear surface as turbulent flow which isreacted with the body to reconvert the dynamic pressure to staticpressure.

6. The method as defined in claim 5 in which the turbulent flow isimparted by reacting the transverse velocity components with the body toproduce angular velocities in the flow.

7. The method as defined in claim 4 in which the transverse velocitycomponents are reacted with the body to impart uniform turbulent flow tothe stream, the dynamic pressure being transmitted to the rear surfaceas uniform turbulence.

8. The method as defined in claim 7' in which the transverse velocity isinduced by constricting the flow stream to pass through the body.

9. The method as defined in claim 4 in which the transverse velocitycomponents are reacted with the body to impart random turbulent flow tothe stream, the dynamic pressure being transmitted to the rear surfaceas random turbulence.

110. The method as defined in claim 9 in which the transverse velocityis induced by constricting the flow stream to pass around the bodywithin a conduit.

llll. A fluid flow device for increasing the rate of flow of a fluidstream relative to the device, said device comprising:

a forward surface and a rear surface coupled with said forward surface;I means for inducing transverse velocity components in the fluid streamalong said forward surface thereby to convert static pressure of thefluid to dynamic pressure and correspondingly thereby reducing staticpressure on said forward surface;

means adjacent said forward surface for reacting with said transversevelocity components to change the direction of said components fortransmission of said dynamic pressure to said rear surface;

and means for transmitting said dynamic pressure to said rear surfacewhereby the conversion of static pressure to dynamic pressure and thetransmission of said dynamic pressure to said rear surface reduces thestatic pressure in said forward surface thereby accelerating said fluidstream relative to said device.

112. A fluid flow device as defined in claim lll further includmg: I

means adjacent said rear surface for reacting with said dynamic pressureto reconvert said dynamic pressure to static pressure on said rearsurface, thereby increasing the static pressure on said rear surface.

l3. A fluid flow device as defined in claim H2 wherein:

said means for reacting with said transverse velocity componentscomprise at least one forward baffle supported by said forward surface;

and said means for reacting with said dynamic pressure comprise at leastone rear baffle supported by said rear surface.

114. A fluid flow device as defined in claim 13 wherein:

said forward surface is a flow-converging surface, and said rear surfaceis a flow-diverging surface;

and said means for inducing said transverse velocity componentscomprises constricting said. flow along said converging surface.

l5. A fluid flow device as defined in claim M wherein:

said device is a venturi nozzle;

and said forward and rear baffles each: comprise a flat plate whichprojects inwardly of said nozzle and lies along a plane offset from andparallel to a radius of said nozzle.

M. A fluid flow device as defined in claim M wherein:

said device is a teardrop-shaped body centrally supported in a tubularflow conduit;

and said forward and rear baffles each comprises a plate which projectsoutwardly of said body and lies along radial planes including thecenterline of said conduit.

v UNITED STATES PATE @FMQE CETIFICATE 0F CQR-EQTHW Patent No. 3, 3 ,9Dated January 25, 1972 Inventofls) EDWIN J KEYSER It is certified thaterror appears in the above-identified! patent and that said LettersPatent are hereby corrected as whom beluws Column 1, line 14, change"shapped" to --shaped-.,

Column 2, line 48, change "12'' to -in-.

Column 8, line 14, after "that" insert a--..

Signed and sealed this 22nd day of August 1972.

(SEAL) Attest;

EDWARD ZMQFLETCHERJR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. The method of reducing static pressure on a leading surface of a bodyin a fluid stream comprising the steps of: inducing transverse velocitycomponents in the fluid stream along the forward surface therebyconverting static pressure of the fluid to dynamic pressure andCorrespondingly thereby reducing the static pressure on the forwardsurface; reacting the transverse velocity components with the body alongthe forward surface to change the direction of the components fortransmission of the dynamic pressure through the fluid stream; andtransmitting the dynamic pressure through the fluid stream away from theforward surface.
 2. The method as defined in claim 1 in which thetransverse velocity components in the fluid stream are reacted with thebody to impart turbulent flow to the stream, the dynamic pressure beingtransmitted away from the forward surface as turbulent flow.
 3. Themethod as defined in claim 2 in which the turbulent flow is imparted byreacting the transverse velocity components with the body to produceangular velocities in the flow.
 4. The method of reducing staticpressure on a forward surface of a body in a fluid stream whileincreasing static pressure on a rear surface of the body, said methodcomprising the steps of: inducing transverse velocity components in thefluid stream along the forward surface thereby converting staticpressure of the fluid to dynamic pressure and correspondingly therebyreducing the static pressure on the forward surface; reacting thetransverse velocity components with the body along the forward surfaceto change the direction of the components for transmission of thedynamic pressure through the fluid stream; transmitting the dynamicpressure through the fluid stream to the rear surface; and reacting thedynamic pressure with the body along the rear surface to reconvert thedynamic pressure to static pressure on the rear surface.
 5. The methodas defined in claim 4 in which the transverse velocity components in thefluid stream are reacted with the body to impart turbulent flow to thestream, the dynamic pressure being transmitted through the stream to therear surface as turbulent flow which is reacted with the body toreconvert the dynamic pressure to static pressure.
 6. The method asdefined in claim 5 in which the turbulent flow is imparted by reactingthe transverse velocity components with the body to produce angularvelocities in the flow.
 7. The method as defined in claim 4 in which thetransverse velocity components are reacted with the body to impartuniform turbulent flow to the stream, the dynamic pressure beingtransmitted to the rear surface as uniform turbulence.
 8. The method asdefined in claim 7 in which the transverse velocity is induced byconstricting the flow stream to pass through the body.
 9. The method asdefined in claim 4 in which the transverse velocity components arereacted with the body to impart random turbulent flow to the stream, thedynamic pressure being transmitted to the rear surface as randomturbulence.
 10. The method as defined in claim 9 in which the transversevelocity is induced by constricting the flow stream to pass around thebody within a conduit.
 11. A fluid flow device for increasing the rateof flow of a fluid stream relative to the device, said devicecomprising: a forward surface and a rear surface coupled with saidforward surface; means for inducing transverse velocity components inthe fluid stream along said forward surface thereby to convert staticpressure of the fluid to dynamic pressure and correspondingly therebyreducing static pressure on said forward surface; means adjacent saidforward surface for reacting with said transverse velocity components tochange the direction of said components for transmission of said dynamicpressure to said rear surface; and means for transmitting said dynamicpressure to said rear surface whereby the conversion of static pressureto dynamic pressure and the transmission of said dynamic pressure tosaid rear surface reduces the static pressure in said forward surfacethereby accelerating said fluid stream relative to said device.
 12. Afluid flow device as defined in claim 11 further including: MEANSadjacent said rear surface for reacting with said dynamic pressure toreconvert said dynamic pressure to static pressure on said rear surface,thereby increasing the static pressure on said rear surface.
 13. A fluidflow device as defined in claim 12 wherein: said means for reacting withsaid transverse velocity components comprise at least one forward bafflesupported by said forward surface; and said means for reacting with saiddynamic pressure comprise at least one rear baffle supported by saidrear surface.
 14. A fluid flow device as defined in claim 13 wherein:said forward surface is a flow-converging surface, and said rear surfaceis a flow-diverging surface; and said means for inducing said transversevelocity components comprises constricting said flow along saidconverging surface.
 15. A fluid flow device as defined in claim 14wherein: said device is a venturi nozzle; and said forward and rearbaffles each comprise a flat plate which projects inwardly of saidnozzle and lies along a plane offset from and parallel to a radius ofsaid nozzle.
 16. A fluid flow device as defined in claim 14 wherein:said device is a teardrop-shaped body centrally supported in a tubularflow conduit; and said forward and rear baffles each comprises a platewhich projects outwardly of said body and lies along radial planesincluding the center line of said conduit.